Actually, mulching is mostly about preventing soil erosion and increasing water retention. When you consider that the original reason for abandoning the orchards is expensive water you may think that burning your orchard residue is setting money on fire.

It is the same with tillage. Conventional farming sprays synthetic fertilizers, only to do tillage which resets the soil and basically throws all the money they put into their fertilizers away, necessitating even more fertilizer usage.